Import Unity Model and Animations to Blender
I know this is an old post, but if anyone experiences the same issue, it's very easy to fix.

To import fbx:


Go to File > Import > FBX



When importing the fbx make sure to 


Select your fbx file
Select armature in Import FBX option Area
Select automatic bones orientation
Select import

If it's not working as expecting, play around the primary and secondary bones options, but usually, if your fbx is working in unity, the automatic option will do it for you.


Good luck, never give up - keep the good work :)